This invention relates to a hydrophilic group-containing AB-type block copolymer having a hydrophilic group-containing polymer chain and a polymer chain having affinity for a resin.
It has been already known that a block copolymer is useful for modifying the surface or interface of a resin and making its effect persistent.
The hydrophilic group-containing AB-type block copolymer of the present invention functions in such a manner that the hydrophilic group-containing polymer chain is oriented to the surface or interface of the resin to be modified, while the polymer chain having affinity for a resin is fixed to the resin. Accordingly, it can be used in various fields in which excellent properties possessed by hydrophilic groups such as water absorption capacity, antistatic properties, electrical conductivity, stain resistance, non-fogging, oil resistance, adhesiveness to metals, glass and ceramics, and compatibility with organisms are desired to be imparted to a resin. Specifically, it can be used for a paint additive, resin additive, surfactant, anti-foaming agent, flocculating agent, dispersant, builder, scale retarder, toner, adhesive, fibers, membrane, sealant, rubber, binder, water-absorptive resin, etc.
An attempt has heretofore been made to synthesize hydrophilic group-containing block copolymers which are expected to have the above mentioned excellent surface or interface modification effect, but has not been successful with radical polymerization methods. Meanwhile, Japanese Laid-Open Patent Publication No. 202261/84 has proposed that a hydrophilic group-containing block copolymer can be synthesized by use of a polymeric peroxide or a polyazo compound.
However, when a hydrophilic group-containing block copolymer is synthesized by the use of a polymeric peroxide or polyazo compound as mentioned above, the molecular weight of the resulting polymer can be controlled with difficulty and further homopolymers are by-produced whereby it is difficult to obtain a block copolymer of high purity.